Well thank goodness no issues Whew ! Nick IMO turning off the class "D" amp is a mistake. Leave it on for 24/7. As suggested MUTE the Pre then turn off. You will definitely hear a difference after 3 days of amp being on. Foe some odd reason class D amps do not like to be turned off. Every one we tried same result.
charles
When I had the Classe' 25 I let that amp run 24/7 It was all solid state so there was no tube wear to worry about. Now when I got that ARC VT-200 the story changed 180 degrees. With 16 output tube the change I did not let that amp run any longer than I needed to.
But it is not only amps, I had an Audio Alchemy DAC (the my son still uses today) that if it got turned off for 10 minutes took three days before it sounded decent again. But there again, it was a really small drain and not tubes to wear out, so I didn't see any harm in keeping ot powered up.
And I have other gear that is warmed up and ready to go in five minutes.........